The present invention relates to devices designed to prevent animals from entering an area, and in particular relates to devices to prevent wild elephants from leaving an elephant sanctuary or reserve and entering an area of human population or cultivated croplands.
The rapid decline of wild elephant populations throughout the world is a well-documented phenomenon. In India, which contains the world""s largest concentration of wild Asian elephants, there remain only an estimated 30,000 elephants in the wild. This tiny population is declining at an alarming rate, making the Asian elephant an ever-increasingly highly endangered species. The two principal reasons for the decline of wild elephant populations are poaching and loss of habitat. While problems with poachers often gamer the news headlines, it is the problem of loss of habitat that presents the greater long-term danger to the existence of wild elephants in India and other parts of the world. Those areas where wild elephants remain also are the areas of the world where human populations are increasing the most rapidly. India, for example, is experiencing a meteoric increase in its human population; this inevitably leads to the expansion of humans further and further into wild elephant areas as people clear new croplands.
The increase in human habitation in wild elephant areas, coupled with the loss of habitat and concomitant loss of food and water resources for the elephants, has led to a catastrophic clash between human and wild elephant populations, which the elephants are losing. The danger to both wild elephants and humans living in close proximity are greatly exacerbated when the habitat area available to wild elephants is reduced. An average adult elephant requires 200 kilograms of food and 200 liters of fresh water per day. As the elephant""s wild territory shrinks, elephants have increasingly turned to raiding crops and food stores maintained by humans in nearby areas. Humans caught in the path of these desperate elephants may be injured or killed. For example, in the State of Chhattisgarh, in far northwestern India along the Pakistani border, wild elephants killed at least 34 people in the period of 2000-2003. In the State of Assam, in northeast India, more than 100 people were trampled to death by elephants during this same period. Assam contains the largest population of wild elephants of any Indian state.
In order to protect their crops and the lives of their families, farmers in the areas near wild elephant populations have turned to killing the elephants who raid their lands. The problem is rapidly increasing in severity. In the state of Assam, for example, only one elephant was killed by farmers in 2000, but 17 were killed by farmers in 2002. Most of the elephants killed by these farmers were poisoned. Sadly, farmers have used even more inhumane methods to deal with the elephant incursion problem. In the southwest Indian State of Kamataka, for example, one group of farmers were reported to have fed wild elephants fruits containing low-grade explosives. The explosives ruptured in the elephant""s mouths, causing them to die a slow and painful death.
The deaths and injuries to both humans and elephants in the wild elephant border areas have led authorities to try and address these problems as best they can. Usually the solution is to simply kill the small number of elephants that are viewed by the local farmers as presenting the greatest threat. In March of 2003, two Asian elephants near Sootea in the state of Assam were put to death by an elephant hunter hired by the state government after a rampage in which the elephants killed 12 people. Such elephant hunts may result in very cruel treatment toward elephants. In addition, there is evidence that such killings provide no solution, since the vacuum left by the death of one or a few elephants in an area is quickly filled by other elephants. A long-term solution cannot be achieved by culling a few elephants from a herd as the forces that cause the problem act upon the herd as a whole.
India and other countries with wild elephant populations have attempted to protect the elephant herds by establishing a system of elephant sanctuaries and reserves. These sanctuaries and reserves, however, are typically rather small, and are highly fragmented across a wide area. Elephants by nature tend to roam over a wide range, and thus confinement of the animals into a small reserve is difficult, greatly increasing the likelihood of disastrous contact between wild elephant and human populations. One potential solution to this problem currently being explored by elephant experts is the creation of xe2x80x9ccorridorsxe2x80x9d of safe passage between reserves. In principle, elephants could travel between reserves in different areas by passing through these narrow corridors, giving each elephant herd a range that is effectively larger than isolated reserves can provide. In order to be effective, however, it would be necessary to somehow prevent elephants passing through these narrow corridors from moving into human populated areas situated along the corridor.
The problem then is how to contain the elephants. Due to their great size and strength, simple fences are a generally ineffective solution to preventing elephant ingress into an area. The principal current method employed for blocking the passage of wild elephants into a populated area involves the digging of trenches. This can be effective in certain terrains and for limited periods of time, but a trench must be quite wide and deep in order to prevent an elephant from crossing. Such trenches are expensive to dig in the first place, and are expensive to maintain since erosion and other natural forces tend to fill in any man-made trenches. As erosion takes place, an elephant may be encouraged to attempt a crossing that may in fact be dangerous, possibly resulting in injury to the elephant. In any event, as the trench fills the elephants will eventually be able to cross if proper maintenance is not performed. Trenches are thus at best a partial solution in certain areas for the prevention of elephant ingress into a human populated area.
While it is possible to construct heavily reinforced, electrified fencing that will restrain elephants, the employment of such fencing over a significant expanse is not practical due to the high cost of such fencing. Solar-powered fences are increasingly being used and, like trenches, are effective in certain regions. But also like trenches, solar-powered fences require constant maintenance. In addition, elephants are capable of detecting regions of weaker voltage in electrified fencing, thus reducing the effectiveness of such fencing if a constant voltage cannot be maintained.
While heretofore no known mechanical methods have been employed to prevent elephant ingress into an area, there are numerous mechanical devices that have been constructed to stop the movement of smaller animals, usually domesticated animals such as cattle, horses, and swine. In particular, many types of so-called xe2x80x9ccattle guardsxe2x80x9d have been in use since the 1800""s throughout the world. The purpose of a cattle guard is to prevent animals from stepping through openings in fences, such as where a railroad line or roadway passes through the fence. The cattle guard is permanently placed in the opening, usually over a trench or other opening in the ground. The use of a cattle guard eliminates the requirement of placing a gate to block the passage. Gates are costly, and may be impractical in some situations, such as when the cattle guard is used at a railroad line passage. Since the movement of cattle is easily blocked by a relatively simple and cheap barbed-wire fence, cattle guard devices are only used in those locations (such as roadways and railroad lines) where fencing cannot be placed.
The typical cattle guard is simply a slatted walkway placed over a shallow trench. The slats are spaced such that a cow will be reluctant to tread on the device for fear of a foot passing through one of the spaces between the slats. Cattle, along with other hoofed animals such as pigs and horses, have a natural fear of treading on such spaces. Thus a simple and effective cattle guard can be constructed at nominal cost to block ingress or egress of such animals.
The prior art does include, however, more complex cattle guard devices, particularly for use across railroad lines. U.S. Pat. No. 848,374 to Jenks teaches a cattle guard for use at railway crossings that comprises a metal frame within which are fitted tube-shaped rollers. If an animal steps upon the guard, the rollers turn, drawing the animal""s hoof toward the gaps between the rollers. The turning of the roller toward the gap serves to discourage the animal from treading on the device. The cattle guard is constructed in modular form, with pieces that may be fitted together to cover a desired area of track. One particular design objective in this device was to eliminate projecting parts, which might injure persons passing over the guard, or catch on train cars as a train passes over the guard.
U.S. Pat. No. 1,406,343 to Carden teaches a cattle guard similar to the Jenks ""374 device, but in place of the cylindrical rollers of Carden ""343 the device of Jenks ""374 substitutes rollers of a frusto-conical shape. These rollers are placed in the metal frame in an alternating pattern. The inventor asserts that this arrangement results in an unusually effective moving surface for the prevention of cattle ingress and egress.
U.S. Pat. No. 1,618,555 to Shaw teaches a railroad cattle guard of still another design. In place of cylindrical or frusto-conical rollers, Shaw ""555 teaches the use of rotating hollow shafts to which blunted spiral blades are attached. The spiral blade is fitted along the shaft in a helical, auger-like fashion. The inventor asserts that when a cow or other hoofed animal steps upon the device, the rotation of the shaft upon which weight is placed will, due to the shape of the spiral blade, push the animal""s foot both in a forward or backward direction, and in a sideward direction, which serves to discourage the animal from crossing.
The prior art directed to the prevention of ingress and egress by hoofed animals, particularly cattle, is inapplicable to the problem of preventing elephant incursion into human populated areas. The anatomy of an elephant""s foot is quite different from that of cattle, horses, swine, and other hoofed animals for which the prior art xe2x80x9ccattle guardxe2x80x9d devices were designed. Elephants have toes rather than hooves, with the toes encased in a thick layer of fatty, fibrous tissue. It is this layer of spongy, protective material that allows an elephant to walk so delicately and silently across all sorts of terrain despite its great bulk. The elephant""s foot has far greater sensitivity than that of any hoofed animal due to this arrangement, allowing the elephant to feel the surface over which It walks. In addition, elephants are far more intelligent than cattle or horses, and are particularly adept at problem solving. Thus a typical slatted cattle guard would present no obstacle whatsoever to an elephant""s passage.
The prior art roller-type cattle guards would also be ineffective against elephants. Elephants are, like most other animals, reluctant to step on a surface that moves when their weight is applied. Each of the prior art cattle guard devices, however, include a frame that surrounds and supports the rollers. Experiments conducted by the inventor hereof indicate that elephants presented with such a simple device may bypass the roller portion of the guard by walking down the framed edge section. When multiple guards are placed side by side, as would be necessary in any practical application to form a barrier to block elephant passage from a protected area, the area in which an elephant may comfortably place its foot is effectively doubled because the two frame edges are butted together. Such an arrangement is a wholly ineffective obstacle In the face of an elephant""s superior problem-solving abilities. An attempt to construct a thinner frame would result in a device that would be crushed by the elephant""s weight, again allowing the elephant to pass over without difficulty. In addition, an elephant may be able to crush the axle/bushing arrangement at the edge of such a frame, thereby rendering the rotation of the rollers ineffective and allowing the elephant to easily step across.
It may also be seen that since prior art cattle guards are designed to allow humans, vehicles, trains, and the like to pass, while blocking cattle and other hoofed animals, there are important limitations on their design. Such devices could not, for example, include elements that would catch on passing vehicles or trains, tear the tires of vehicles passing over, or present a risk of injury to humans attempting to tread across. A device to address the problem of preventing elephant incursion into populated areas, however, need not be capable of supporting the passage of vehicles, trains, or the like. Instead, a device is needed that can simply be laid down to form a border over which elephants cannot cross. The needed device would thus be more analogous to a fence than a cattle guard in application. As a result, the possible design features that may be applied in a device to solve this problem need not be limited in the same fashion as cattle guard designs, and may in fact, in some embodiments, include elements that would block the passage of both elephants and humans. The device should preferably, however, be portable so that the exact location of the desired elephant barrier may be moved as needed from time to time.
In summary, it may be seen that prior art methods to stop ingress and egress of hoofed, domesticated animals are wholly inadequate to address the problem of preventing elephants from entering populated areas near wild elephant habitat. What is desired is a simple, effective means to prevent wild elephants from encroaching into populated areas, which is preferably inexpensive and simple to construct using mostly used or salvage materials widely available in those areas of the world where wild elephant populations remain. The present invention overcomes the limitations of the prior art devices and addresses the unique characteristics and abilities of the wild elephant in order to develop a practical and effective elephant incursion prevention apparatus as described below.
The present invention is directed to an apparatus comprising one or more modular and mobile units that may be used to protect both wild elephants and the humans who live near wild elephant populations by preventing elephant incursion into the human populated areas. In particular, the device may be used to prevent wild elephants from entering areas of human population in search of food and water. The present invention is specifically designed in response to the unique physiology and problem-solving capabilities of the elephant. The inventor hereof has tested the present invention with elephants maintained on an elephant sanctuary located in the United States. This sanctuary provides a home for unwanted elephants formerly kept by zoos and circuses. Because of their long years of interaction with humans, and in particular their exposure to all sorts of machinery and mechanical devices, these elephants likely have less trepidation concerning mechanical devices than wild elephants. The inventor hereof therefore believes that any device capable of preventing the ingress and egress of these elephants will be even more effective in limiting the travel of wild elephants.
The present invention comprises a heavy frame fitted with a series of rollers. The rollers are designed to turn when an elephant places his weight upon them. The present invention further comprises a guard placed along the lateral edges of the frame to prevent an elephant from using the edges of the frame as a means to bypass the rollers. The guard is preferably of such a shape as to xe2x80x9cpinchxe2x80x9d the elephant""s foot when weight Is applied. The inventor has discovered that an elephant has a natural fear of placing its foot into an area where it may be pinched, and the high degree of sensitivity in the elephant""s foot enhances the effectiveness of this technique. The elephant encountering this guard will draw its foot back upon touch, thereby preventing the elephant from passing over the various embodiments of the present Invention. The guard is specifically designed to prevent any injury to the elephant or any possibility of trapping the elephant""s foot. The guard will also prevent the elephant from crushing the rollers at the point where they are attached to the frame, thereby rendering it impossible for the elephant to disable the roller motion of the device in this manner and thereby pass over the device.
The present invention also comprises various embodiments of the invention with additional features to further discourage passage by elephants. In one embodiment, the rollers include blunt, smooth triangular flanges protruding along their length. Experiments conducted by the inventor hereof have shown that these flanges serve to further discourage elephants from treading upon the rollers, without causing injury to the elephant""s sensitive feet. In another embodiment, the present invention may include means for dispensing natural repellents and deterrent compounds that repel elephants. In still another embodiment, the present invention may include an electrical conductor that provides a mild shock to an elephant whose foot or trunk touches the conductor.
The present invention is designed to be easily transported by towing behind a vehicle or a trained elephant, and is thus both mobile and reusable. In the preferred embodiment of the present invention, rails forming part of the frame may be used as towing skids for this purpose. Attachment loops may be included for connection to towing chains or ropes. In addition, attachment loops may be used to chain multiple units of the present invention together to form a barrier of any desired length.
It is therefore an object of the present invention to provide for a device to prevent the incursion by elephants into a human populated area without injuring elephants who encounter the device.
It is a further object of the present invention to provide for a device that may be laid together in various configurations to block an area of any perimeter shape or size from elephant ingress or egress.
It is a further object of the present invention to provide for a device to prevent incursion by elephants that may be constructed simply and inexpensively, at least partially from used or salvage materials commonly found in areas of the world where wild elephant populations exist.
It is a further object of the present invention to provide for a device to prevent incursion by elephants that is easily portable, and may be easily towed behind a vehicle or trained elephants for placement and movement as desired.
It is a further object of the present invention to provide for a device to prevent incursion by elephants with a guard to prevent elephants from, circumventing rollers incorporated into the device and to prevent elephants from crushing the rollers or the roller mounting means.
It is a further object of the present invention to provide for a device to prevent incursion by elephants that may incorporate one or more specific mixtures of biologically meaningful chemicals into one or more rollers that serve the dual purposes of warning elephants and also as a direct deterrent.
It is a further object of the present invention to provide for a device to prevent incursion by elephants that may incorporate multiple methods to prevent elephant incursion, comprising one or more of rollers, flanged rollers, and electrified conductors.
These and other features, objects and advantages of the present invention will become better understood from a consideration of the following detailed description of the preferred embodiments and appended claims in conjunction with the drawings as described following: